Calotype Paper Negatives

The term “Calotype,” derived from the Greek words “Kalos” (meaning “beautiful”) and “tupos” (“impression”), refers to the first photographic process developed.

At its core, the calotype process involves precipitating silver iodide within the fibers of the paper, sensitizing it with an excess of silver ions, imprinting a latent image through exposure to natural light, and then developing the image using gallic acid.

I wrote an article providing a detailed overview of Calotype chemistry and Talbot’s workflow in 1840 that I think you will find helpful.

Temporal Symphony: Cycles of Change Full Workflow

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Calotype Paper Negatives – Short

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Greenlaw Calotype Paper Negative – Full Workflow

How the Calotype Paper Negative Aligns with My Creative Framework

Photography is not just a technical pursuit but a profound expression of one’s vision, values, and emotions. I’ve long been drawn to the unique characteristics of 19th-century processes in my work, and the calotype paper negative is a cornerstone of my artistic practice. What captivates me about this historical technique is its inherent aesthetic qualities that align seamlessly with my Creative Framework—Resilience, Transformation, and Connection. Each of these pillars finds its voice in the textural, imperfect, and soulful qualities of the calotype paper negative, offering a visual and emotional language that resonates deeply with my vision.

Resilience: The Strength in Imperfection

The calotype process is a testament to resilience in its very creation. Unlike modern photography, which pursues technical perfection and razor-sharp detail, calotypes embody the idea that beauty is found in imperfection. The handmade nature of each paper negative, complete with its fibers, subtle inconsistencies, and organic textures, represents the strength of embracing imperfections.

This is a direct reflection of the Resilience pillar in my Creative Framework. The calotype’s quiet strength lies in its ability to endure despite its delicate composition. Its soft, almost ethereal quality emphasizes endurance in nature and the subtle, steadfast moments that often go unnoticed. The visible imperfections remind viewers that resilience is not about being unscathed but about carrying marks that tell stories of time and experience.

Transformation: Embracing Change and Evolution

Every calotype I create embodies transformation. The process itself—layering chemistry onto paper, exposing it to light, and watching an image emerge—mimics the very essence of change and growth. The calotype’s aesthetic, with its deep shadows and soft gradations of tone, symbolizes the passage of time and the metamorphosis that occurs within that continuum.

In a world where everything is constantly shifting, the calotype is an enduring reminder of transformation’s beauty. Unlike digital images that often feel static and uniform, each calotype is unique. The final image may vary due to subtle changes in chemistry, temperature, or even the texture of the paper. These variations mirror life’s unpredictable transformations, aligning perfectly with my framework’s focus on evolution and the cycles of renewal.

Connection: A Bridge Between Past and Present

The calotype paper negative serves as a bridge connecting the present to the past. Its roots trace back to the 19th century when photography was still more art than science, more mystery than certainty. This process, steeped in history, invites a connection not only between artist and medium but between eras. Creating and viewing a calotype draws the observer into a conversation with the past, fostering a sense of continuity and shared human experience.

In my work, Connection is about the bonds between people, places, and nature. The calotype’s soft, painterly quality evokes a feeling of harmony that blurs the lines between memory and reality, allowing viewers to feel more than see. The textures and shadows echo themes of roots and bonds, providing an intimate narrative that resonates with the soul. Each photograph feels like an echo from another time, rich with stories waiting to be rediscovered and shared.

Why Calotype Matters in My Artistic Journey

Choosing the calotype paper negative is not just a technical decision but a deeply personal one. This process allows me to express ideas that go beyond sharp details and perfect compositions. The calotype’s aesthetics—its soft focus, tonal richness, and inherent imperfections—speak to the emotional landscape that my Creative Framework seeks to explore. It is a process that requires patience, commitment, and an embrace of the unpredictable, aligning perfectly with the Resilience, Transformation, and Connection pillars that guide my work.

Through the calotype, I can tell stories that honor the journey over the destination, stories that find strength in imperfections, beauty in transformation, and depth in connection. This handmade approach aligns with my belief that art should evoke, resonate, and endure—mirroring life itself.

Chemical Evolution of the Calotype

The calotype paper negative process, invented by William Henry Fox Talbot in 1840, revolutionized early photography by introducing a method to create reproducible negatives on paper. Over the next decade, prominent European figures refined the process, each contributing significant advancements that addressed its limitations. Below is a timeline highlighting key innovations and contributors.

1840 – William Henry Fox Talbot (English)

• Invention of the Calotype Process: Talbot introduced a three-step process: iodizing, exciting, and developing paper negatives using silver nitrate, potassium iodide, acetic acid, and gallic acid.  
• While groundbreaking, Talbot’s method was complex, requiring precise timing and preparation. The unstable chemistry also posed challenges for photographers.

1847 – Because Talbot’s process was unreliable, various improvements soon emerged. Louis-Désiré Blanquart-Evrard (1802 – 1872) presented to the public a process in which chemicals were applied to paper by immersing or floating, not by brushes. Image quality was improved tremendously. Instead of sensitizing the negative with the so-called “gallo-nitrate of silver,” which very often destroyed paper even before it was exposed, Blanquart-Evrard, in the first step, treated the paper only with silver nitrate. He used gallic acid only as a developer. Guillot-Saguez (1807-1866) fundamentally altered Talbot’s and Blanquart-Evrard’s calotypes. He remarkably simplified the process by eliminating the first silver nitrate bath. Guillot-Saguez iodized the paper, applied silver nitrate, exposed it, developed it, and fixed it. This greatly simplified the process and made it stable and repeatable. From here on, we are no longer talking about calotypes but paper negatives.

1847 – Louis-Désiré Blanquart-Evrard (First Major Refinement) (French)

Louis-Désiré Blanquart-Evrard (1802 – 1872) refined Talbot’s process by applying chemicals to the paper by immersing or floating, not by brushes. Image quality was improved tremendously. Instead of sensitizing the negative with the so-called “gallo-nitrate of silver,” which very often destroyed paper even before it was exposed, Blanquart-Evrard, in the first step, treated the paper only with silver nitrate.

Blanquart-Evrard’s major contributions to the calotype process, made primarily in 1847, were pivotal in advancing photographic techniques and accessibility:

Paper Coating and Preparation Techniques:

• In 1847, Blanquart-Evrard introduced improved methods for coating photographic paper, enhancing the consistency and quality of negatives and prints. This made the calotype process more practical and accessible for photographers.

Albumenized Paper:

• He popularized the use of albumen-coated paper during the late 1840s and early 1850s, which significantly increased image sharpness and tonal range. This innovation became the standard for photographic printing in the mid-19th century.

Commercialization and Dissemination:

• In the early 1850s, Blanquart-Evrard established a photographic printing company in Lille, one of the first large-scale photographic printing operations. This enterprise helped spread photography as an artistic and scientific medium by making high-quality prints more widely available.

• Throughout the late 1840s and early 1850s, his processes emphasized reproducibility and standardization, addressing the inconsistencies of earlier methods and setting the stage for broader adoption of photography.

Blanquart-Evrard’s contributions, especially in 1847 and the years following, were instrumental in transitioning photography from a niche experimental practice to a standardized and widely used medium.

1847 – Dr. Guillot-Saguez (Simplified The Workflow – New Era of Paper Negatives) (French)

• Single-Solution Iodizing: Guillot-Saguez simplified Talbot’s two-step iodizing method, using only potassium iodide to prepare the paper. Silver nitrate was added later during the exciting stage, offering greater control.  
• Indicator Color Change: His method produced a tell-tale violet or blue tint when potassium iodide oxidized, signaling when the exciting solution had fully penetrated the paper.  
• This innovation laid the groundwork for subsequent advancements, including Gustave Le Gray’s pre-waxed paper technique.
• Technically, Guillot-Saguez refined the calotype process in a new direction, which was considered a paper negative from this point forward.

1851 – Gustave Le Gray (French)

• Pre-Waxed Paper Process: Building on Guillot-Saguez’s simplifications, Le Gray introduced pre-waxing the paper to improve its strength and reduce light scattering.  
• Enhanced Practicality for Travel: Pre-waxed paper could be prepared in advance, transported without degradation, and developed later, making it ideal for field photography.  
• Le Gray’s process was more stable and versatile than plain calotypes, bridging the gap between the calotype and the collodion processes.

1856 – Alexander Greenlaw (Scottish)

• Adapting to Hot Climates: Greenlaw found that Guillot-Saguez’s method excelled in tropical conditions, where other processes often failed. He tweaked the chemistry to work in the hot climate of India. His name became associated with this variation, which persisted into the 20th century.
• Greenlaw did not pre-wax the paper like Le Gray. His workflow was a dry process, and then he waxed post-mortem after the paper negative was fixed and dried.

1860s – Pelegry Tannin Process (French)

• Tannin-Based Workflow: Pelegry introduced a tannin-modified iodizing step that extended the shelf-life of prepared calotype papers to six months or more, addressing the instability of earlier processes.
• Pyrogallic Acid Developer: Utilized pyrogallic acid in the development stage to enhance the compatibility of the tannin-modified calotypes, achieving greater control over tonal range and density.
• Significance: This adaptation provided unprecedented flexibility for photographers, who could now prepare negatives well in advance without compromising quality. The innovation particularly suited photographers working in remote locations or under time constraints.

Key Contributions and Legacy

Each contributor addressed specific limitations of Talbot’s original method:

• Blanquart-Evrard improved Talbot’s original workflow by immersing or floating the paper during sensitization versus using a brush. He also modified Talbot’s original “gallo-silver nitrate” chemistry to only be silver nitrate in the first step of the process. He is also responsible for improving paper preparation and commercialization.
• Guillot-Saguez simplified and stabilized the iodizing stage, effectively creating the paper-negative process of the Victorian era and beyond.
• Le Gray enhanced practicality for travel with pre-waxed paper.
• Greenlaw modified the Guillot-Saguez improvements and ensured viability in extreme climates.
• Pelegry extended the shelf-life of paper negatives using a tannin method and introduced new development techniques with pyrogallic acid.

By the late 19th century, the calotype process reached a point of chemical refinement, balancing sensitivity, stability, and practicality. These innovations highlight the collaborative and iterative nature of photographic development, transforming early photography into a more accessible and versatile medium for artists and scientists alike.

Modern Calotype Chemistry Overview

The calotype process is an early photographic technique involving a paper negative, developed by William Henry Fox Talbot in the 19th century. In this process, a paper is sensitized with silver halides that make it light-sensitive, allowing for the creation of negatives that can be used to produce positive prints.

I personally follow the Greenlaw and Le Gray workflows for my calotype paper negatives. If I am working in my darkroom when creating floral still lifes in my outdoor studio, I use the Greenlaw method. Anytime that I am away from the darkroom, I use the pre-waxed Le Gray method. As described in the section above, both Greenlaw and Le Gray methods were based on the Dr. Guillot-Saguez refinements to the original Talbot calotype process. Dr. Guillot-Saguez simplified and stabilized the original calotype process by using a single iodizing step. This single modification made the calotype paper negative process stable and accessible for all photographers moving forward.

Here’s a detailed breakdown of the chemistry involved in preparing a calotype paper negative using potassium iodide, potassium bromide, glacial acetic acid, and silver nitrate. I note the slight differences between Greenlaw and Le Gray methods. Fox Talbot did not initially use potassium bromide when he iodized the paper. This modification came a little later when photographers realized the benefits of including it and mixing it with potassium iodide.

Step 1: Sensitizing the Paper with Silver Iodide and Silver Bromide

Preparation of the Paper with Potassium Iodide (KI) and Potassium Bromide (KBr):

• The calotype paper is first coated with potassium iodide (KI) and potassium bromide (KBr). This coating prepares the paper by introducing iodide (I⁻) and bromide (Br⁻) ions onto the paper’s surface.

The paper is then dried before the next step.

The Le Gray method pre-waxes the paper before the paper is iodized. This is a big difference and Le Gray adds rice water (starch) and Lactose to the Iodizing solution. The other notable difference between Greenlaw and Le Gray methods is that I need to sandwich the calotype between two sheets of glass when using the Greenlaw workflow and I can use a regular modern film holder when using the pre-waxed Le Gray method. This single improvement greatly simplifies the fieldwork and significantly reduces the weight of the holders without the heavy glass plates. The penalty of this benefit comes at the expense of much slower exposure times (30 seconds at F4 in bright sunlight with Greenlaw versus 4 minutes with Le Gray).

Silver Nitrate Solution and Double Decomposition:

• After drying, the paper is brushed or immersed in a solution of silver nitrate (AgNO₃) mixed with glacial acetic acid.
• The silver nitrate reacts with the iodide and bromide ions on the paper through a double decomposition reaction, forming insoluble silver iodide (AgI) and silver bromide (AgBr).
• These silver halides (AgI and AgBr) are light-sensitive compounds crucial for capturing images.
• The Greenlaw sensitizer consists of AgNO3 6.3% and glacial acetic acid 6.3%, and Le Gray, with the pre-waxed version, uses AgNO3 7% and glacial acetic acid 9%.

The reactions are as follows:

Byproducts: Potassium nitrate (KNO₃) is a byproduct of both reactions. Since it is water-soluble, it can be easily washed away during processing.

Role of Glacial Acetic Acid (CH₃COOH):

• Glacial acetic acid acts as a stabilizer and acidifies the silver nitrate solution, which helps control the reaction rate. A lower pH slows the formation of silver halides, allowing for a more uniform coating on the paper and reducing fogging (unwanted darkening) of the negative.
• The acidic environment also slightly enhances the silver halides’ sensitivity to light, which is advantageous for capturing more detailed images.
• At the end of this step, the paper now has a layer of light-sensitive silver iodide (AgI) and silver bromide (AgBr), making it ready for exposure to light.

 Step 2: Exposure to Light

• A photochemical reaction occurs when the sensitized paper is exposed to light in a camera. The silver halides (AgI and AgBr) begin to break down in these areas, reducing silver ions (Ag⁺) to metallic silver (Ag⁰).
• This metallic silver forms a latent (invisible) image on the paper, which will be visible in the development stage.
• The Greenlaw version requires a 30-second exposure at F4 in bright sunlight (EV-15), and Le Gray requires about 4 minutes.

 Step 3: Development of the Image

Chemical Development:

• After exposure, the paper is treated with a developing agent, often gallic or pyrogallic acid, combined with additional silver nitrate. (Greenlaw and Le Gray workflows use gallic acid like Talbot’s original invention and only the tannin-based workflow of Pelegry uses pyrogallic acid.)
• Gallic acid acts as a reducing agent, accelerating the reduction of silver ions to metallic silver in the exposed areas.
•  In this step, the latent image becomes visible as the metallic silver darkens the areas exposed to light.
• I use the same developer chemistry and ratios for Greenlaw and Le Gray calotypes.

Step 4: Fixing the Image:

The developed calotype is then “fixed” to remove any unreacted silver halides that were not exposed to light. Fixing is typically done with a solution of sodium thiosulfate (historically called “hypo”) or potassium cyanide (though the latter is toxic and was later phased out).

Fixing dissolves the unreacted silver halides, leaving only the metallic silver image on the paper. This prevents further darkening or fogging when exposed to light.

Byproducts and Waste

Potassium Nitrate (KNO₃): Formed as a byproduct when potassium iodide and potassium bromide react with silver nitrate. This is soluble in water and can be washed away.

Unreacted Silver Compounds: Removed during the fixing stage. Proper disposal is necessary to handle any residual silver compounds safely, as they can be environmentally harmful.

This is why the final archival wash is so important to determining the life of any silver-based negative or print. As mentioned in the video, I only use distilled water for the calotype paper negative process to ensure I am not introducing chlorine or other unknown contaminents into the process.

Summary

1. Sensitizing: Potassium iodide and potassium bromide on paper react with silver nitrate to form silver iodide (AgI) and silver bromide (AgBr), light-sensitive compounds.

2. Exposure: Light exposure reduces silver ions to metallic silver in the exposed areas, creating a latent image.

3. Development: Gallic acid (or similar agent) reduces more silver, darkening the exposed areas and making the image visible.

4. Fixing: Sodium thiosulfate removes unreacted silver halides, stabilizing the image against further light exposure.

Through its unique chemical interactions, the calotype process enables the creation of a negative image that can be used to produce multiple positive prints, establishing it as the first negative-to-positive photographic technique. This method and salt print laid the groundwork for all modern photography, serving as the foundational process from which contemporary photographic practices evolved.

Le Gray’s Process (1851)

“AMONGST the discoveries of the present day, Photography may be considered as the one likely to render the greatest service to art.

Its influence upon painting must be considerable, for at the same time that it removes many difficulties with which the artist has to contend, it raises the public taste by accustoming them to view nature in all her fidelity, frequently accompanied with exquisite taste and sentiment.

Since its first discovery, Photography has made rapid progress, especially as regards the instruments employed in its practice, it now remains for the artist to raise it to its proper position among the fine arts.

It is my belief that the future success of Photography rests entirely on the paper process; and I cannot, therefore, too strongly recommend the amateur to direct his attention to this branch of the art. He will obtain upon paper as much finish and more artistic effect than upon glass. The pictures upon the latter are certainly very fine but artistically hard, and give often a false appearance as regards the tones of the lights and shadows, not affording an impression true to nature. Pictures upon glass by the aid of Collodion, offer certainly some advantages in the rapidity of the action and exquisite finish; this is of great importance in portraiture, but its fragility made me abandon it after the discoveries I made in 1849.

The success of my process rests entirely on the fabrication of the paper. By the carrying out the method of preparation which I have laid down in the following pages, a good picture cannot fail to be the result. I think every one will agree with me that the paper process is far more agreeable, more convenient for travelling, lighter to carry, and not fragile like glass. I think, therefore, that the results hitherto obtained by the glass process cannot for one instant counterbalance the advantages possessed by the paper.

GUSTAVE LE GRAY“

Le Gray’s original publication was in French, but it was translated to English in 1853 and again, with minor revisions, in 1855. I have included the PDF documents for each via the links for each year.

Calotype Negative History

Willliam Henry Fox Talbot’s next breakthrough came between the years of 1840 and 1841, when he further refined the steps of the negative-to-positive process. (During the course of his experiments he even considered the option of creating direct positive images which he called leucotypes.) The inventor, however, began to have better success with a new technique: the developed out negative, known as a calotype. The calotype was a latent image process. The visible image was produced only by further chemical development. Like the photogenic drawing negative, Talbot could generate multiple positive prints of a single image from the calotype.

To produce a calotype, Talbot created a light-sensitive surface by coating a sheet of paper, usually writing paper, with a solution of silver nitrate. He dried the paper to some degree and coated it with potassium iodide to produce silver iodide. Prior to exposing the negative in the camera, Talbot gave the paper a final coating of a solution of silver nitrate mixed with acetic and gallic acids. The sensitized paper was then exposed in the camera.

After exposure, Talbot discovered he could bring out the latent image, which had formed on the negative but was not yet visible, by washing the paper again in silver nitrate mixed with small quantities of acetic and gallic acids. Talbot’s application of latent image technology greatly increased the photographic sensitivity of the negative and thus reduced the necessary exposure time in the camera. This technique, known as a developed out process, brought out the visible image with the use of chemicals.

The final step entailed fixing the calotype with hyposulfite of soda (hypo) or halides (potassium iodide and potassium bromide). Calotypes fixed with potassium iodide exhibited a yellow highlight tone. To produce a print with greater detail, Talbot often waxed the negative after processing. Wax penetrated the paper fibers making the negative more translucent. This process allowed more light to come through during printing and produced a print with less visible paper fibers.

While historically some have used the word “calotype” in reference to both early negative and positive images, the term “calotype” here refers to the paper negatives created with the process as developed by Talbot and used by the inventor, his circle of friends, and other amateur photographers of the time.

From Calotype to Paper Negative

William Henry Fox Talbot patented his calotype process in 1841. Because of the patent restrictions in England on his invention, the calotype process only achieved partial success there. In Scotland, where no patent restrictions existed, professional photographers such as David Octavius Hill and Robert Adamson experimented with and refined aspects of Talbot’s method including various chemical and optical techniques.

With no patent restrictions in France as well, French photographers also had freedom to experiment with the method. Hippolyte Bayard, Louis Désiré Blanquart-Evrard, Gustave Le Gray, Édouard Baldus, Henri Le Secq, Frédéric Flachéron, and other French photographers modified Talbot’s calotype process considerably.

Gustave Le Gray, for example, waxed the paper before the sensitizing step, while Louis Désiré Blanquart-Evrard prepared or sized paper with a mix of milk serum and albumen until it was transparent. The term “paper negative” here refers to paper negatives that were significantly altered by photographers and thus not technically the same as Talbot’s calotype process.

I create calotype paper negatives and make salt prints because these historical processes align deeply with the narrative of my work.

The soft, ethereal qualities of the calotype paper negative and the delicate tones of salt prints evoke a sense of memory, loss, and the passage of time.

By embracing the imperfections and organic textures that come with these methods, I can communicate the fragility and emotional depth that form the core of my artistic journey.

These processes are not just technical choices—they are integral to the storytelling within my images, reflecting a connection to the past while inviting introspection and reflection.

Why I Create Calotype Paper Negatives

In my artistic endeavor, a deeply personal exploration borne from the heartache of losing my daughter, Abby, I have found a profound connection with the historical technique of Calotype paper negatives. This choice, deeply intertwined with my emotional journey and artistic expression, resonates with the very core of my being.

Why do I gravitate towards Calotype paper negatives in all of my work now? The answer lies in the unique, almost tangible soulfulness that this medium brings.

The Calotype, with its roots stretching back to the 1830s, possesses a distinct texture and quality that modern techniques cannot replicate. Each handmade negative is not just a medium for an image; it’s a canvas of my emotions, an imprint of my journey through grief and remembrance. -Tim Layton

The softness and rich texture of the Calotype negatives align beautifully with the narrative of my project. The way the paper fibers impart a dreamy character to the images aligns with my desire to capture more than mere visuals. These negatives help me translate the blur of memories, the weight of emotions, and the path of healing into visual form.

Working with Calotype paper negatives is an immersive, hands-on process. There’s something deeply therapeutic in handling the materials, sensitizing the paper, and watching the images emerge in the darkroom. This physical eagement with the art form creates a visceral connection between my inner turmoil and its external expression.

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The grain structure introduced by the paper base adds another layer of artistic depth. It’s not just about creating photographs; it’s about crafting a narrative that weaves together the strands of loss, love, and memory. The ability to directly manipulate these negatives — whether through selective bleaching, penciling, or other techniques — allows me to communicate and express my emotions in a way that is profoundly personal.

Calotype paper negatives also offer unique capabilities in terms of lighting conditions. Their preference for bright and sunny conditions provides me with opportunities to create in lighting environments that are often challenging for other photographic methods. This aligns perfectly with my vision, allowing me to explore the interplay of light and shadow in a manner that is both challenging and rewarding.

Moreover, each Calotype negative is unique, much like the moments and memories I cherish of Abby. The uniqueness of these negatives, and the prints derived from them, is invaluable in my pursuit of personal fine art. They stand as testaments to individuality, to the distinct journey each of us undertakes through life and in the face of loss.

In essence, my use of Calotype paper negatives is not just a technical decision but a deeply symbolic one. It represents a bridge between the past and present, a connection to the historical origins of photography, and a reflection of my own journey through the landscapes of grief and healing. Through this medium, I find not only a method of artistic expression but a means of connecting with my emotions, of honoring Abby’s memory, and of finding a semblance of peace in the wake of indescribable loss.

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It was an overcast day and it was sprinkling rain and I decided to push the envelop and see if I could make a Calotype in these unfavorable conditions. I was able to make something work with a low-light EV 10 scenario and 20 minute exposure. I used my 11 1/2 inch F4 Verito lens wide open at F4 to make this painterly soft Calotype.

History and Evolution of Calotype Paper Negatives

The calotype, also known as the Talbotype, was one of the earliest photographic processes invented by British scientist William Henry Fox Talbot in 1841. This invention introduced the concept of creating paper negatives, which allowed photographers to produce multiple positive prints from a single exposure, a groundbreaking advancement in the early development of photography. Over the years, several key figures improved the calotype process, resulting in various adaptations that enhanced the technique.

View some of Talbot’s Salted Paper Prints From Calotype Negatives.

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Early Beginnings and Talbot’s Experiments (1830s–1840s)

Before Talbot invented the calotype, he experimented with photogenic drawing in the 1830s. It involved placing objects on light-sensitive paper coated with silver chloride and exposing them to sunlight, creating silhouetted images. Talbot continued refining this process, striving to create detailed images using cameras.

In 1841, Talbot patented the calotype process, which allowed for producing negative images on paper. Unlike the daguerreotype, these negatives could be contact-printed to create multiple positive prints, a single image on a metal plate. Talbot’s process used silver iodide to create light-sensitive paper, and after exposure, the paper negative was developed with gallic acid.

Calotype (Talbotype) 1841 Process as described by Towler in the Silver Sunbeam, 1873 edition.

Key Characteristics of Calotype Paper Negatives:

1. Soft, Pictorial Aesthetic: The texture of the paper used in calotypes created softer images, often with visible fibers, giving the photographs a painterly appearance.
2. Reproducibility: The calotype allowed for the creation of multiple positive prints from a single negative, revolutionizing the reproduction of photographs.
3. Paper Negative Limitations: The paper used for calotypes sometimes introduced grain or texture into the image, which made it difficult to capture fine detail, especially compared to the sharper daguerreotypes.

Details of Talbot’s Original Calotype Method

View some of Talbot’s Salted Paper Prints From Calotype Negatives.

Summary of Major Revisions and Evolution of the Calotype

Several important figures contributed to the evolution and refinement of the calotype process since the patent of the Calotype by Fox Talbot in 1841. These modifications improved the technique’s practicality and quality, helping photographers achieve better results under a wider range of conditions.

Louis Désiré Blanquart-Evrard (1843)

• Significance: Blanquart-Evrard made substantial improvements to Talbot’s original calotype process. One of his key innovations was applying chemicals to the paper by floating or immersing it rather than brushing, which ensured a more uniform and consistent coating. Additionally, Blanquart-Evrard streamlined the sensitization process by using only silver nitrate on the iodized paper instead of the more complex gallo-nitrate of silver solution and introduced gallic acid as the developer. These changes simplified the calotype process, making it faster, more reliable, and more accessible for photographers to achieve consistent results. His innovations helped to popularize the calotype method during its time.
• Blanquart-Evrard was a cloth merchant from Lille, France, who learned the calotype process from his druggist, a student of the inventor of the calotype, William Henry Fox Talbot. In 1847, Blanquart-Evrard became the first to publish the procedure for the calotype negative/positive paper process in France. He specialized in printing and issuing portfolios of photographs by other photographers. Still, perhaps his most significant contribution was the introduction in 1850 of the albumen paper print process, the primary printing medium until gelatin papers superceded it in the late 1800s.
• Blanquart-Evrard also established a photographic printing business in 1851, further helping to popularize the calotype and other photographic techniques by producing prints on a larger scale. His contributions played a critical role in improving the practicality and appeal of the calotype process during its time. (References: wiki, Getty)

Amélie Guillot-Saguez (1847)

• Significance: The Guillot-Saguez process marked a pivotal improvement over Talbot’s original calotype method by fundamentally simplifying and altering the process. Guillot-Saguez eliminated the first silver nitrate bath and instead iodized the paper in an initial step. He then applied silver nitrate in a later step before exposing the paper to light, followed by fixing and washing the negative. This adjustment streamlined the workflow and marked a significant shift in the calotype process, effectively making it a true paper negative process from that point forward. His modifications enhanced both the reliability and accessibility of the calotype, making it more practical for photographers.

Gustave Le Gray (1851)

• Significance: Le Gray was instrumental in advancing the calotype by introducing waxed paper negatives. His method involved waxing the paper before it was sensitized with silver salts, significantly improving the images’ sharpness and detail. This method reduced the appearance of fibers and increased the negative’s transparency, allowing for more precise exposure and greater detail in prints. Le Gray’s technique was prevalent in landscape photography and became the standard for many European photographers.
• As noted by Towler in the 1873 Silver Sunbeam, Le Gray’s waxed calotype was the choice of most practitioners. “Several distinguished photographers have improved the calotype process, including Blan-quart-Evrard, Legray, Baldus, Geoffray, Tillard, etc. Amongst all these improvements and extensions, Legray’s wax-paper process is the most extensively employed.”

Alexander Greenlaw (1856)

• Significance: Greenlaw, a colonel in the British army, refined the calotype process for use in field photography. His work primarily involved using a modified waxed paper method, which he developed while photographing architectural sites in India. Greenlaw’s refinements made the calotype more practical and durable, especially in hot and challenging climates. His version of the process simplified the process, allowing for easier preparation and handling, and resulted in sharper, more translucent negatives.
• Overview of Greenlaw’s process from the Silver Sunbeam, 1873 edition.

Pelegry (1879)

Significance: The Pelegry Process represented the final major improvement to the calotype before the turn of the century when flexible film was the rage of photography. It introduced a tannin bath after the sensitizing process to allow paper negatives to be stored for months before exposure, which is ideal for fieldwork. Exposure times were similar to the Greenlaw variant, faster than earlier calotypes. The developer formula also changed due to the tannin preservative, requiring a pyrogallic acid developer combined with a silver nitrate additive. This combination allowed the negatives to be developed by inspection, further enhancing the photographer’s control over the final image.

Reference: LA PHOTOGRAPHIE des peintres, des voyageurs et des tourists, 1879 (Photography for Painters, Travelers, and Tourists)) (PDF, French)

Legacy of the Calotype

While the wet collodion process eventually overtook the calotype and film overtook collodion, the calotype played a pivotal role in the history of photography. It introduced the concept of negative-positive reproduction, which became the foundation for modern photography. The soft, painterly quality of calotype and paper negative images also laid the groundwork for the Pictorialist movement, where photographers embraced a more artistic and expressive approach to photography.

Today, the calotype is appreciated for its historical significance and aesthetic qualities. Contemporary photographers and historians continue to explore and recreate the calotype process for its unique visual characteristics and role in shaping photography’s development.

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Advanced Details of the Calotype Evolution

Introduction to Talbot’s Calotype Process

In 1841, William Henry Fox Talbot patented the Calotype process, introducing a method that produced a paper negative from which multiple positive prints could be made. This negative-positive workflow was a significant advancement over the Daguerreotype, which yielded a single, non-reproducible image. Talbot’s process laid the foundation for modern photography by enabling image reproduction.

Chemistry and Workflow of the Original Calotype Process

Selection of Paper

• High-Quality Paper: Talbot used fine paper, such as Whatman paper, known for its purity and consistency.

Sensitizing the Paper

• First Silver Nitrate Application:
  • Chemical Used: Silver nitrate solution.
  • Process: The paper was coated with silver nitrate to introduce silver ions.

Iodizing the Paper

• Chemical Used: Potassium iodide solution.
• Process: The silver-coated paper was immersed in potassium iodide, forming light-sensitive silver iodide (AgI) on the paper.
• Washing and Drying: Excess potassium iodide was washed away, and the paper was dried.

Sensitization Before Exposure

• Chemicals Used: Silver nitrate, gallic acid, and acetic acid (forming the gallo-nitrate of silver solution).
• Process: Just before exposure, the iodized paper was coated with this sensitizer to increase light sensitivity.

Exposure in the Camera

• Process: The sensitized paper was exposed in the camera, where light reduced silver ions to metallic silver, creating a latent image.
• Exposure Times: Varied from several seconds to minutes due to low sensitivity.

Development of the Image

• Chemicals Used: Gallic acid solution with a small amount of silver nitrate.
• Process: The latent image was developed by immersing the paper in this solution, intensifying the image until it became visible.

Fixing the Image

• Chemical Used: Sodium thiosulfate (“hypo”).
• Process: The developed image was fixed by dissolving unreacted silver halides, rendering it permanent.

Washing and Drying

• Process: The paper was thoroughly washed to remove residual chemicals and then dried.
• Waxing (Optional): To increase transparency for printing, the negative could be waxed.

Purpose of Each Chemical

• Silver Nitrate: Introduces silver ions to form light-sensitive compounds.
• Potassium Iodide: Reacts with silver nitrate to create silver iodide.
• Gallic Acid: Acts as a developing agent, reducing silver ions to metallic silver.
• Acetic Acid: Stabilizes the sensitizing solution and enhances development.
• Sodium Thiosulfate: Fixes the image by dissolving unreacted silver halides.

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Timeline of Major Revisions and Evolution of the Calotype

1841 – William Henry Fox Talbot Introduces the Calotype

• Contribution:
  • Patented the Calotype process, introducing the negative-positive workflow.
  • Enabled multiple positive prints from a single paper negative.

1843 – Louis Désiré Blanquart-Evrard’s Improvements

Key Innovations:

• Uniform Chemical Application:
  • Applied chemicals by immersing the paper rather than brushing, ensuring even coating.
• Simplified Sensitization:
  • Used only silver nitrate on iodized paper, eliminating the complex gallo-nitrate of silver solution.
• Gallic Acid Developer:
  • Introduced gallic acid as a separate developing agent.
• Impact:
  • Simplified the Calotype process, making it faster and more reliable.
  • Enhanced accessibility for photographers.

1847 – Amélie Guillot-Saguez’s Simplification

Key Innovations:

• Eliminated Initial Silver Nitrate Bath:
  • Iodized the paper first, then applied silver nitrate just before exposure.
• Impact:
  • Streamlined the workflow, making the process more practical and reliable.

1851 – Gustave Le Gray’s Waxed Paper Negatives

Key Innovations:

• Pre-Exposure Waxing:
  • Waxed the paper before sensitization to fill pores and increase transparency.
• Improved Sharpness:
  • Reduced graininess, resulting in sharper, more detailed images.
• Impact:
  • Enhanced image quality, particularly beneficial for landscape photography.
  • Allowed photographers to prepare negatives in advance.

1851 – Édouard Baldus’s Enhancements

Key Innovations:

• Combination of Processes:
  • Merged aspects of the Calotype and wet collodion processes.
• Improved Paper Negatives:
  • Used a variation of the waxed paper process to achieve greater detail and contrast.
• Impact:
  • Produced negatives with improved sharpness and tonal range.
  • His work was instrumental in architectural and landscape photography.

1852 – Geoffray’s Cerolein Process

Key Innovations:

• Use of Cerolein:
  • Introduced cerolein (a component derived from beeswax) in the iodizing solution.
• Enhanced Transparency:
  • Improved the translucency of paper negatives without the need for waxing after processing.
• Process Details:
  • Papers were immersed in a solution containing cerolein, iodides, and other additives.
  • Sensitization and development followed similar steps to previous methods.
• Impact:
  • Simplified the process by reducing steps.
  • Improved negative quality and ease of handling.

1853 – Tillard’s Turpentine and Wax Process

Key Innovations:

• Turpentine and Wax Solution:
  • Dissolved white wax in turpentine, adding iodine and castor oil.
• Sensitization with Nitrate of Zinc:
  • Used a sensitizing solution containing nitrate of silver and nitrate of zinc.
• Impact:
  • Increased sensitivity and reduced exposure times.
  • Produced negatives with good detail and contrast.
• Benefits:
  • The process was rapid and suitable for fieldwork.

1854 – Humbert de Molard’s Wet-Paper Negative Process

Key Innovations:

• Wet-Paper Process:
  • Introduced a method where the paper remained wet during exposure.
• Simplified Iodizing:
  • Used iodide of ammonium for faster preparation.
• Process Details:
  • Paper was iodized, sensitized, and exposed while still moist.
  • Development used gallic acid with acetate of ammonia.
• Impact:
  • Significantly reduced exposure and development times.
  • Improved efficiency for portrait and outdoor photography.

1855 – Prichard’s Improved Calotype Process

Key Innovations:

• Combination with Glass Plates:
  • Mounted sensitized paper onto glass plates for better stability.
• Simplified Washing:
  • Introduced a method for washing the paper after sensitization to prevent uneven development.
• Process Details:
  • Sensitized paper was attached to glass and exposed.
    • Development used gallic acid with a small amount of silver nitrate.
• Impact:
  • Improved sharpness and reduced issues with paper movement.
    • Made the process more consistent and reliable.

1856 – Alexander Greenlaw’s Modified Calotype Process

Contribution:

• Adapted the Calotype for hot, humid climates while photographing in India.

Key Innovations:

• Elimination of Pre-Exposure Waxing:
  • Omitted waxing before sensitization and exposure.
• Chemical Adjustments:
  • Added potassium bromide and free iodine to the iodizing solution.
  • Modified sensitizing and developing solutions.
  • Included spirit of camphor in the developer.
• Post-Exposure Waxing:
  • Waxed negatives after processing to improve transparency.
• Impact:
  • Made field photography more practical and reliable in challenging environments.
  • Achieved high-quality images without pre-waxing.
• Publication:
  • Detailed in the 1873 edition of “The Silver Sunbeam.”

1879 – Pelegry’s Tannin Process

Contribution:

• Introduced tannin preservation and development by inspection.

Key Innovations:

• Tannin Bath:
  • Allowed negatives to be stored for months before exposure.
• Pyrogallic Acid Developer:
  • Enabled development by inspection with silver nitrate additive.
• Impact:
  • Provided flexibility for photographers to prepare negatives in advance.
  • Offered greater control over image development.
• Publication:
  • Described in Pelegry’s book “La Photographie des Peintres, des Voyageurs et des Touristes” (1879).

Summary of Additional Contributions

• Édouard Baldus:
  • Improved paper negatives by combining processes.
  • Enhanced detail and contrast in architectural photography.
• Geoffray’s Cerolein Process:
  • Simplified the preparation of negatives.
  • Eliminated the need for post-processing waxing.
• Tillard’s Turpentine and Wax Process:
  • Introduced a rapid process suitable for field photography.
  • Achieved good image quality with reduced exposure times.
• Humbert de Molard’s Wet-Paper Process:
  • Increased efficiency by exposing wet paper negatives.
  • Benefited portrait and outdoor photographers.
• Prichard’s Improved Calotype:
  • Combined paper negatives with glass plates for stability.
  • Enhanced sharpness and consistency.

Conclusion

The evolution of the Calotype process was marked by numerous innovations from various photographers who sought to improve its practicality, efficiency, and image quality. Each contributor addressed specific challenges:

• Simplification and Accessibility:
  • Blanquart-Evrard, Guillot-Saguez, and Prichard streamlined the process, making it more accessible to photographers.
• Improved Image Quality:
  • Le Gray, Baldus, and Greenlaw enhanced sharpness and detail through pre-waxing, chemical adjustments, or combining processes.
• Adaptation to Environmental Conditions:
  • Greenlaw and Tillard modified the process for use in hot and humid climates, crucial for field photographers.
• Extended Usability and Efficiency:
  • Humbert de Molard and Pelegry introduced methods that allowed for immediate or delayed development, providing flexibility.
• Innovative Materials and Chemicals:
  • Geoffray and Tillard experimented with new substances like cerolein and turpentine solutions to improve the process.

Despite eventually being surpassed by more advanced technologies like the wet collodion process and gelatin silver emulsions, the Calotype’s development was instrumental in shaping photographic techniques. The collaborative efforts of these innovators laid the groundwork for modern photography by enhancing the negative-positive workflow, image reproducibility, and the medium’s artistic potential.

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Historical Evolution of the Calotype

• 1724: Johann Heinrich Schulze discovered that silver compounds are light-sensitive, creating the first photograms but unable to fix them.
• 1777: Carl Wilhelm Scheele discovered the first fixer using ammonia on silver chloride.
• 1802: Thomas Wedgwood attempted to fix photos on paper, creating early photograms.
• 1816: Joseph Nicéphore Niépce made the first photograph (negative) using a camera obscura and silver chloride.
• 1823: Niépce produced the first photo using bitumen.
• 1831: Louis-Jacques-Mandé Daguerre improved sensitivity using iodine with silver.
• 1833: Antoine Hercule Romuald Florence took the first photo using a camera obscura and silver chloride, applying the negative-positive principle.
• 1835: Daguerre fixed the first positive photograph from a negative.
• 1839: Hippolyte Bayard developed direct positive printing but failed to patent it. Daguerre patented the daguerreotype process. William Henry Fox Talbot showed his photograms and negatives. John Frederick William Herschel discovered sodium thiosulphate as a better fixer. Rev. J. B. Reade found that gallic acid increases paper negative sensitivity.
• 1840: Talbot began developing a new process for latent images.
• 1841: Talbot patented the Calotype process, improving exposure time and using iodized paper and gallic acid developer.
• 1847: Louis-Désiré Blanquart-Evrard improved the calotype process, using floating chemicals and silver nitrate. Jacques-Michel Guillot-Saguez simplified this process, leading to the transition from calotype to paper negatives. Claude Félix Abel Niépce de Saint-Victor made the first albumenized negative on glass.
• 1851: Henri Victor Regnault suggested using pyrogallic acid for quicker development. Gustave Le Gray introduced waxed-paper negatives. Frederick Scott Archer and Le Gray discovered the wet plate collodion process.
• 1884: Eastman Company’s faster bromide paper briefly revived paper negatives before the shift to celluloid films.

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Historic Literature

The Calotype Process: A Hand Book to Photography on Paper, Thomas Sutton BA.
It is probably the definitive article of the 1850s; if you read this book and put the information into practice, you will learn a lot and enjoy the journey. Academics and understanding can only take you so far. You need to invest time in the darkroom and the field making calotypes to truly understand and master the process.

Practical Photography on Glass and Paper, Charles A Long.

“There are two processes by which the author has succeeded in obtaining most excellent results, and he now purposes to give such plain and simple directions in both of them, that if followed carefully and in detail, by the merest tyro in the art must lead him to success”

-Charles Long

LA PHOTOGRAPHIE des peintres, des voyageurs et des tourists (1879), Arsene Pelegry (PDF, French) – Pelegry’s process represents the final update to the Calotype and paper negative process in the 19th century. I developed a modern-day version of this process based on Pelegry’s original text.

If you read these books and combine the wisdom in both, you will have a clear path to making high-quality calotype paper negatives.

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Calotype Paper Negative Qualities

Calotype paper negatives hold a special place in the creation of Pictorialist handmade fine art images due to several unique qualities:

Softness and Texture: Calotype negatives often exhibit a softness in detail and a rich texture, which is highly prized in Pictorialism. This quality is due to the paper fibers, which impart a distinctive, almost dreamy character to the images, different from the sharpness typical of glass or film negatives.

Unique Grain Structure: The Calotype’s paper base introduces a unique grain structure not present in other types of photographic negatives. This grain adds an artistic element to the images, contributing to their aesthetic appeal.

Handmade Quality: Pictorialists valued the handcrafted aspect of their work, and Calotype negatives align well with this philosophy. Coating, sensitizing, and developing the paper negatives is labor-intensive and allows for a high degree of personal expression and control.

Tonal Range: Calotypes are known for their wide tonal range, which allows them to capture subtle variations in light and shadow. This characteristic is particularly appealing in fine art photography, where mood and atmosphere are often more important than precise detail.

Historical and Artistic Significance: The calotype process is one of the earliest photographic techniques. Its use connects contemporary Pictorialist work with the origins of photography, adding depth and context to the artwork.

Manipulation and Control: Paper negatives’ physical nature allows for direct manipulation, such as selective bleaching, penciling, or other techniques to alter or enhance the image. This level of control is attractive to artists who wish to imbue their work with a personal touch.

The uniqueness of Each Print: Each Calotype negative is unique, and the prints made from these negatives have a singular quality. This uniqueness is highly valued in fine art, where distinguishing from mass-produced images is crucial.

Calotype paper negatives are cherished in Pictorialist handmade fine art photography for their unique aesthetic qualities, historical significance, and the extensive creative control they offer to the artist.

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The Beginning of Modern Photography

Patented in 1841, the Calotype was a pioneering technique that utilized paper negatives. This innovation was the brainchild of British inventor Henry Fox Talbot (1800-1877), marking the advent of the first negative-positive photographic process. This groundbreaking method created multiple positive prints from a single negative, laying the foundation for modern photography.

Talbot’s journey in photography began in 1834 at Laycock Abbey, England, within his family’s ancestral home. Despite his significant contribution to photography, Talbot’s reputation was marred by his litigious and financially driven approach to his invention. He was known for aggressively enforcing his patent rights, suing those who used his process without authorization, and charging substantial licensing fees.

While I don’t employ Talbot’s original recipes or methods, my work closely aligns with the principles of Calotypy. “Calotype” describes the specific photographic process developed by Henry Fox Talbot, while “Calotypy” refers more broadly to the art or practice of making photographs using this process. Both terms are rooted in the same historical photographic technique. This makes me a Calotypist who uses the advanced chemistry and science that evolved after the original invention.

A Calotypist is a person who practices or specializes in the Calotype process, the early photographic technique invented by William Henry Fox Talbot in the 1830s-1840s. A calotypist creates paper negatives using Talbot’s method, which allows for producing multiple positive prints, typically through the salt print process. Calotypists were among the earliest photographers who embraced this historic technique, favoring its soft, painterly qualities and ability to produce reproducible images.

The Greenlaw Improved Calotype

I utilize a variant of the Calotype process attributed to Alexander Greenlaw (1818-1870). Greenlaw’s improved process version was first documented in the “Photographic News” in January 1869. It was also mentioned in the 8th edition of John Towler’s “The Silver Sunbeam” (1873), seemingly using Greenlaw’s language, and in the 7th edition of “Abney’s Instructions in Photography” (1886). This acknowledgment in various publications is notable, considering the Calotype’s peak popularity was in the mid-1850s. Remarkably, references to this process appeared well into the early 1900s, demonstrating its enduring relevance. Now, in the 21st century, the Calotype process, in its various forms, remains a viable and historically rich photographic technique.

Alexander Greenlaw’s version of the calotype was a simplified adaptation of the original process, particularly suited for hot climates like India, where he practiced photography for at least 14 years. His method, published in The Photographic News in 1869, was seen as a more practical and efficient approach, removing unnecessary complexities found in earlier versions. Greenlaw’s process used potassium iodide and potassium bromide, with a silver nitrate bath for sensitizing and gallo-nitrate of silver for development, producing large-format negatives admired for their boldness and effect.

Greenlaw’s Process – The Silver Sunbeam, 1873

Colonel Alexander Greenlaw, an officer in the British East India Company’s army, made significant contributions to photography, particularly with his work at Hampi, India. While his initial interest in photography remains unclear, Greenlaw’s talent was recognized in 1855 when he received a second-class medal for his photographic work in Madras. His most notable achievement came around 1856 when he photographed the ruins of Hampi using the calotype method, innovatively adapting it to India’s challenging climate. His simplifications and enhancements of this process were among the last significant developments in Calotypy.

Despite publishing his method in 1869, Greenlaw’s work slipped into obscurity until 1980, when Eddie Gibbons, a retired British army officer, rediscovered his negatives in London. These photographs, the only visual records of Hampi’s ruins before major archaeological efforts, have since been crucial for historical studies and restoration efforts. Greenlaw’s images provide a comprehensive visual survey of Hampi and highlight the extent of destruction over the centuries.

His work, particularly in the context of Hampi, stands as the earliest complete photographic record of an ancient site in India. Colonel Greenlaw’s contributions, particularly after he died in 1870, underscore the importance of photographers in documenting historical sites and narratives.

Watch this fascinating video by Dr. George Michell who brings this story to life.

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Greenlaw Calotype Chemistry Overview

I have included a basic overview for each part of the chemistry from iodizing the paper through fixing and washing.

Iodize Paper

• Potassium iodide (KI)
• Potassium bromide (KBr) 
• DH20

– Potassium Iodide (KI): This is a key component in sensitizing the paper. Potassium iodide reacts with silver nitrate in the sensitizing step to form silver iodide, which is light-sensitive.

KI Photographic Characteristics:

• Grain Size and Structure: Influences the resolution and fineness of the image. Smaller grains of silver iodide lead to higher resolution.
• Spectral Sensitivity: Primarily sensitive to blue and ultraviolet light, which impacts the tonal rendition in the final image.

– Potassium Bromide (KBr): This acts as a secondary halide, forming silver bromide when reacted with silver nitrate. Silver bromide is also light-sensitive and contributes to the overall sensitivity and characteristics of the photographic image.

KBr Photographic Characteristics:

• Grain Size and Quality: Silver bromide grains are typically finer than silver iodide, contributing to the overall image quality.
• Spectral Sensitivity: Like silver iodide, it’s mainly sensitive to blue and ultraviolet light.
• Contrast Control: Potassium bromide can affect the contrast of the final image. It’s often used to modify or control the development process, influencing the image’s tonal range.

– Distilled Water (DH20): The solvent for both potassium iodide and potassium bromide, ensuring they are evenly distributed in the solution to react uniformly with the paper.

Sensitizer 

• AgNO3 (Silver Nitrate)
• Glacial acetic acid 
• DH20

– Silver Nitrate (AgNO3): This reacts with potassium iodide and potassium bromide on the paper to form light-sensitive silver halides (silver iodide and silver bromide).

– Glacial Acetic Acid: It’s used to acidify the silver nitrate solution, which helps preserve the light-sensitive halides and control the reaction rate with the halides in the paper.

– Distilled Water (DH20): The silver nitrate and acetic acid medium, ensuring uniform application on the paper.

Developer Stock Solution A

• Gallic acid
• DH20

– Gallic Acid: This developing agent reduces exposed silver halide (from the sensitized paper) to metallic silver upon exposure to light.

Gallic acid is chemically denoted as C₇H₆O₅. It is a naturally occurring organic acid found in various plants.

Characteristics of Gallic Acid as a Developing Agent

Chemical Structure:

   – Gallic acid is a trihydroxybenzoic acid, with three hydroxyl groups attached to a benzene ring.

Physical Properties:

   – Appearance: White to yellowish crystalline powder.

   – Solubility: Moderately soluble in water, more soluble in hot water, and very soluble in alcohol and ether.

Role in Photographic Process:

   – Developing Agent: It’s used as a developing agent in the photographic process, especially in historical photographic techniques like the Calotype.

   – Reduction of Silver Halides: Gallic acid reduces exposed silver halides to metallic silver upon exposure to light, which creates the image.

Reaction Speed:

   – Relatively Slow Reactivity: Compared to modern synthetic developers, gallic acid reacts more slowly. This allows for more controlled development and finer grain structure in the image.

Image Quality:

   – Tonal Quality: Tends to produce images with a wide range of tones, giving a softer and more nuanced rendition compared to harsher chemical developers.

Comparison to Other Developing Agents

Speed of Development:

   – Gallic acid is slower than many modern developing agents, such as hydroquinone or metol. This slower speed allows for greater control but requires longer development times. My Calotype development time ranges between 7 and 20 minutes compared to 1.5 to 2 minutes for silver gelatin prints. 

Grain and Resolution:

   – It typically produces a finer grain structure in the developed image, leading to higher resolution and detail compared to some faster-acting developers.

Tonal Range:

   – Provides a wide tonal range, which can be particularly desirable in certain types of photography, like fine art or historical reproduction.

Safety and Environmental Impact:

   – Being a natural compound, gallic acid is generally considered safer and less toxic compared to many synthetic chemicals used in modern developing processes.

Historical and Artistic Value:

   – Its use in historical photographic processes like the Calotype adds an element of historical authenticity and can be of interest to those pursuing traditional photographic techniques.

In summary, gallic acid as a developing agent offers distinct advantages in terms of control, tonal quality, and grain structure. It is slower acting than many modern developers, which can be beneficial for detailed work and achieving a specific artistic effect, but may not be as practical for rapid processing. Its use is often more aligned with artistic, historical, or experimental photography rather than fast-paced commercial or journalistic settings.

– Distilled Water (DH20): Solvent for gallic acid.

Developer Stock Solution B

• DH20 (Distilled Water)
• AgNO3 (Silver Nitrate)
• Glacial acetic acid

– Distilled Water (DH20): Silver nitrate and acetic acid solvent.

– Silver Nitrate (AgNO3): Enhances the development of the image by providing additional silver ions.

– Glacial Acetic Acid: Regulates the pH and acts as a preservative.

Glacial acetic acid is chemically denoted as CH₃COOH. It is essentially concentrated acetic acid and is one of the purest forms of acetic acid, typically containing at least 99% acetic acid.

Characteristics of Glacial Acetic Acid

Physical Properties:

   – Appearance: Clear, colorless liquid.

   – Odor: Has a strong, pungent vinegar-like smell.

   – Freezing Point: Freezes at 16.7°C (62°F) into a clear crystalline solid, hence the name “glacial.”

Chemical Nature:

   – Acidity: It is a weak acid but highly concentrated.

   – Reactivity: Reacts with bases, oxidizing agents, and many metals.

Role in Photographic Development:

   – Acidification: Used to acidify the developing solution in photography. This lowers the pH, which can slow down the development process and give more control over it.

   – Preservative: Helps in preserving the light-sensitive silver halides in the photographic emulsion.

   – Buffering Agent: Can act as a buffering agent to maintain the desired acidity level in the developer solution.

Comparison to Other Developing Agents

Speed and Control:

   – Compared to other acids or developers, glacial acetic acid provides a slower, more controlled development process. This allows for greater manipulation and precision in image development.

Preservation and Stability:

   – It helps in preserving the integrity of the photographic emulsion better than some other agents, contributing to longer shelf-life and stability of the developer solution.

Versatility

   – While it’s primarily used for acidification and preservation, its role can be more varied than some developing agents that have a more singular purpose.

Safety and Handling:

   – Glacial acetic acid is relatively safe to handle with proper precautions but is more corrosive and irritating compared to diluted acetic acid or some milder developing agents. Adequate ventilation and protective gear are necessary.

Environmental Impact:

   – As an organic compound, it is generally less harmful to the environment compared to some synthetic chemicals used in development processes.

Glacial acetic acid offers a unique combination of controlled development, preservation, and buffering capabilities in the photographic process, differing from other developers in its concentration, acidity, and impact on the development rate and emulsion stability.

Working Developer 

• Solution A + Solution B in varying dilutions based on variables.

– Combination of Solution A and B: This mixture is used during development to reduce the exposed silver halides to metallic silver, creating a visible image.

Fixer

• Sodium thiosulfate 

– Sodium Thiosulfate: This solution dissolves the remaining light-sensitive silver halides that were not reduced during development, making the image permanent and light-insensitive.

Hypoclear

• Sodium sulfite 

– Sodium Sulfite: This removes the thiosulfate from the paper, reducing the likelihood of image deterioration over time.

Wash

• Tap water wash for clearing and archival purposes.

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Calotype Overview by George Eastman House

History of Fox Talbot & Calotype Negatives